offensive vs obnoxious

offensive is a noun but obnoxious is not a noun.

Word	Noun	Adjective	Verb	Adverb
offensive	Yes	Yes	No	No
obnoxious	No	Yes	No	No

offensive (noun)	obnoxious (noun)
the action of attacking an enemy

offensive (adjective)	obnoxious (adjective)
unpleasant or disgusting especially to the senses	causing disapproval or protest
causing anger or annoyance
for the purpose of attack rather than defense
morally offensive
violating or tending to violate or offend against
causing or able to cause nausea